Mentor Mothers (MM) are women living with HIV who are experienced users and navigators of HIV services, particularly PMTCT. Public health interventions engaging MM to support other HIV-positive women for linkage and retention in PMTCT and treatment services has been tested in South Africa, and has been adopted and applied in several other African countries. Similar MM programs have also been adopted and implemented in Nigeria since 2007; however, objective evaluations of MM impact on PMTCT service uptake and retention have not been performed to date.